DIG-S 1.2 Air box removal (to change air filter/access coil packs and spark plugs/oil filler cap)

SplanK

Site Supporter
Today I explored the Micra's HR12DDR engine a bit more. My aim was to see how I could access:
1. Air filter
2. Coil packs/spark plugs

As the engine bay is compact it’s a bit fiddly and Nissan seem to have gone with a odd design compared to in the past which made it a bit quirky when putting it back together!

Removal
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1. To make life a little bit easier you can remove front trumpet, just simply twist and remove. Note the rubber bush highlighted in yellow. It’s just push in and pull out - nothing secures it in place other than a bit of rubber grip

2. There are 2 clips securing the airbox (red box).

3. The box should then pull away. What you will see when you take it off is 3 tabs which sit in 3 corresponding holes on the mounting part. You have to pull the top bit away then lift up. Keeping in mind the rubber mounts highlighted in yellow

And that’s it, air filter and coil packs are now fully visible to do whatever you want!
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Refitting
Refitting was a PITA and requires a bit of force. Easiest way I did it was to guide the right hand side locating tab in first, and then push the top part in. If you take a look at the top you will see there is a bit sticking out which interferes stopping you making it an easy fit. The left hand side is the same, just requires a bit of manual persuasion. Keeping in mind again the rubber bushes!

Refitting the trumpet is again pop in and twists until it locks in place

Can’t find any official documentation regarding this, all it says in the owners manual is take it to a dealer!

Airbox notes:
Smallish air filter, but I suppose with the engine being forced induction you can get away with it more
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MAF sensor quite exposed and easily damaged. Previous Nissans I have played with usually have a wire mesh, or a throttle plate in the way! It states in the owners manual *ONLY* to use dry type filters. So oiled K&N filters are a no no (saying that, it’s been a no no for a while really!)
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Part of the airbox is actually not used and inside the removable part is a blanking plate which cuts off around 1/3rd of the airbox and it cuts off part of the air filter as well. This was evident when I inspected the air filter dirt side, the part with the blanking plate was much much cleaner than the other side. Maybe this is done to reduce noise, but I would have thought cutting this bit out may help it breath a little better.
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Hi!

Nice topic!
The blanking plate has a resonator function (less air turbulence in admission). Do not remove it.

What engine oil do you will use?
 
OP
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SplanK

Site Supporter
There is a resonator on the airbox trumpet, and previous resonator removals never really gained much noise!

As the car is still under warranty - i'm not touching it, but thought it was worth pointing out.

I have 2x 'free' services with Nissan so not really bothered about what oil goes in just yet, but I suspect its going to be different than the usual 10w40 I've used in previous nissans!
 
I'm looking for a basic DIY cleaning of the air-filter and the pollen-filter (the one inside the cabin) for my K13 Micra with a K9K heart. Can anybody guide me to the relevant material.

TIA
 
Recently, I decided to replace the air filer of my Note dig-s. While the old air filter (Nipparts) is quite easy to remove/install, it is really hard when I install the replacement one (Ashika). It took more than 1 hour and I nearly broke the air box clips.

I then realized that is because Ashika's rubber strip is a bit too thick. By reusing the old rubber strip with the new filter, it was really simple to install.
 
Mine whistles when I rev it or drive it since I took out the little panel in the air filter box, I also made up a ram air system with a scoop in the grille. I run it with the green fabric type filter, not a paper filter. And it goes and sounds great.

Sent from my SM-A505FN using Micra Sports Club mobile app
 
Mine whistles when I rev it or drive it since I took out the little panel in the air filter box, I also made up a ram air system with a scoop in the grille. I run it with the green fabric type filter, not a paper filter. And it goes and sounds great.

Sent from my SM-A505FN using Micra Sports Club mobile app
No negatives at all after removing that little panel? I was worried it may run lean return the increased airflow. This one in the picture, correct?
I've already tapped over the the little holes in the trumpet resonator which increased the whistle a little. My hr12ddr is in our 2015 Nissan Note Nismo
 

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SplanK

Site Supporter
The removal of this blade in the intake box won't increase airflow into the engine, but noise may increase by a marginal amount. The overall airbox design does a surprisingly good job at quietening down the supercharger!

However, this baffle blade may have a 'damping' effect which can help smooth out airflow on engines where there is a dead zone on the intake - IE there is a small period where no cylinder is taking in air, and thus creating a backwards pulse in the intake (similar to water hammer) and this baffle will have been tuned to help handle this. Removing it may ironically reduce overall power/smoothness but by a negligible amount
 
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